Sewing machine with improved basting stitch mechanism

ABSTRACT

A sewing machine in which a simplified basting stitch mechanism is incorporated. A circular moving loop taker is cooperable with the needle in the production of stitches. Intelligence record means are movable supported on the frame of the machine drivable by the rotary mainshaft of the machine. The intelligence record means are operatively connected with the said loop taker so as to effect a preselected modification of the effective circular movement threof with respect to said needle to thus prevent the formation of stitches.

[451 Apr. 16, 1974 United States Patent [191 Ross [ SEWING MACHINE WITH IMPROVED 10/1954 112/159 112/178 1/1970 l-lamlett..............................

k d U M 0 4 9 H 3 39 240 040 999 223 c e b e u 0 M m S e m m 6 m ma H I a mu G: m m T m S e A v B m N U or Firm--Marshal1 J. Breen; Chester -1 e d e m h C S H r m e w m a a a J .nt Z wa m .mm nmA Canada [73] Assignee: The Singer Company, New York,

[ ABSTRACT A sewing machine in which a simplified basting stitch mechanism is incorporated. A circular moving loop [22] Filed: Jan. 24, 1973 211 Appl. No.: 326,328

taker is cooperable with the needle in the production of stitches. lntelligence record means are movable supported on the frame of the machine drivable by the rotary mainshaft of the machine. The intelligence record means are operatively connected with the said loop taker so as to effect a preselected modification of the effective circular movement threof with respect to said needle to thus prevent the formation of stitches.

12 Claims, 3 Drawing Figures 2 H Aoo 8 1M5 m mmu m m HWN mhl 6 unr "mam L w C d 5nd .I UhF 11]] 218 555 [1.1.

References Cited UNITED STATES PATENTS 3,465,698 9/1969 Hacklander..................... 112/158 R 3,696,769 10/1972 Sawada..;,...........................112/159 SEWING MACHINE WITH IMPROVED BASTING STITCH MECHANISM BACKGROUND OF THE INVENTION The present invention relates to a sewing machine of the type in which a rotary hook co-operates with the needle of the machine in the formation of stitches and in which a basting stitch mechanism is incorporated.

The value of the basting stitch is well known. It is customarily regarded as a temporary stitch for the purpose of securing two or more pieces of fabric together in fixed relationship such as during the construction of a garment. The spacing between stitches is unusually long in order to facilitate removal of the thread which may be accomplished by pulling of the free thread to unravel the entire series of unlocked stitches.

It has heretofore been known to provide for the formation of such basting stitches by utilizing various expedients. One commonly employed basting stitch mechanism is disclosed in U.S. Pat. No. 3,559,601 issued Feb. 2, 1971 to Tullman. Simply stated, the mechanism provides for skipped stitches by disconnecting the needle bar of the machine from its endwise reciprocation driving means. One disadvantage of this expedient is that with extended use the clearances between co-operating elements tend to change resulting in a noise build-up during operation of the machine. Also, on occasion interference between certain of the moving parts occurs with resultant possibility of damage to such parts.

Another prior technique for effecting skip-stitching is the provision of an obstruction in the throat plate of the machine whereby the needle loop is prevented from forming. In this regard reference may be had to the disclosure of U.S. Pat. No. 3,361,100 issued Jan. 2, 1968 to Bono. It has further been appreciated heretofore that stitch formation can be accomplished by changing the position of the shuttle hook with respect to the needle, effected by bodily shifting the shuttle sidewise. U.S. Pat. No. 3,490,401 issued Jan. 20, 1970 to Hamlett discloses such an arrangement which is peculiar to side facing bobbin-type machines.

There has been a need, therefore, for a simplified basting stitch mechanism which does not require periodic disconnection of the needle bar and the needle bar driving means, latching arrangements for the needle bar, and which is reliable and does not involve risk of damage to any moving parts.

SUMMARY OF THE INVENTION It is one object of the invention to provide a sewing machine having a basting stitch mechanism incorporated therein which is adapted to effect a change in timing between the needle of the machine and the circularly moving loop taker without disruption of the reciprocation of the needle bar.

It is another object of the invention to provide a sewing machine with a basting stitch mechanism incorporated therein in which a simple advancement or retarding of the circularly moving loop taker is achieved to thereby insure production of a desired basting stitch.

According to the present invention there is provided in a sewing machine having a frame, a needle bar mounted for endwise reciprcation therein, stitch forming instrumentalities including a thread-carrying needle carried by said needle bar and a circularly moving loop taker co-operable with said needle in the production of stitches, and means, including a rotary main shaft, for driving said needle bar and said circularly moving loop taker, the combination of intelligence record means movably supported on said frame and adapted to be operatively connected to said rotary main shaft, and means for operatively connecting said intelligence record means to said circularly moving loop taker for effecting a circular movement of said looptaker with re- .spect to said needle to prevent the formation of stitches.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be more fully comprehended it will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a sewing machine incorporating the invention, the frame of the machine being shown by phantom lines;

FIG. 2 is an exploded view of the split loop taker shaft and its associated elements including the loop taker; and

FIG. 3 is an enlarged view of portions of the split loop taker drive shaft, the overlying sleeve and the mode of operative interconnection according to the invention, the view being partly broken away and in section.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1 of the drawings there is shown a sewing machine 10 in phantom comprising the customary machine bed 11, upright arm 12, horizontal arm 13 and sewing head 14. A hand wheel 15 is generally provided at the end of the arm shaft (not shown). In order to form the stitches the stitch sewing instrumentalities comprise the needle 16, carried for endwise reciprocation by needle bar 17, and the hook l8 co-operable with the needle. A presser bar 19 provided with a presser foot 20 is for the purpose of exercising control over the material being stitched in order to assist in feeding of the material past the needle and hook (in cooperation with a feed dog not shown) and in preventing upward movement or flagging of the material which adversely affects stitch formation. It will be understood that the present invention has utility with sewing machines with or without the capability of producing the various types of ornamental stitches generally available on current sewing machines although the presently preferred embodiment is in connection with a machine capable of zig-zag operation. A skip-stitch cam is positionable on the cam stack of the machine, and functions in a manner to be hereinafter described.

Positioned in the upper portion of the machine is a form of intelligence record means depicited here as a stack of pattern cams 21. When basting is to be effected an operator-controlled lever 22 is utilized to place a skip-stitch cam 23 in operative engagement with a cam follower 24 formed as part of a lever 25 which is pivotably mounted in the frame of the machine as by shoulder screw 26. It will be observed that lever 25 is desirably provided with an upturned portion 24 which serves as the cam follower, a finger 27 thereof projecting into the path of rotation of cam 23 for actuation by the cam. One end of the lever 25 is provided with gear teeth 28 which serves as a sector gear adapted for engagement with mating gear teeth 29 on a collar 30 secured fixedly to a generally vertically extending timing shaft 31.

Timing shaft 31 is journaled at its lower end in a bracket 32 secured to the frame of the machine. The lower end of the shaft is rigidly secured beneath the machine bed to one end of a link member 33. The other end of the link member has pivotably secured thereto a horizontally extending arm 34. Connection is made such as by an end flange 35 and screw 36. The horizontal arm should be constructed so as to be relatively rigid since it must be capable of transmitting the force occasioned by rotation of the timing shaft and pivotal movement of link member 33 to one end of a second pivotably mounted link 37 connected to the horizontal arm by shoulder screw 67. The other end of this second link member is pivotably mounted such as by shoulder screw 38 in the frame of the machine.

As shown, link member 37 is formed with a pair of off-set portions 39 and 40, one advantage of such a configuration being the capability of shortening horizontal arm 34 with the achievement of the same mechanical advantage for the link member 37. As will be seen more clearly from FIG. 2 a bifurcated yoke member 41 is journaled into the link member 37 intermediate its ends by virtue of a pin extension 42 formed on the bight of the yoke member. The pin extension is dimensioned to fit rotatably within aperture 43 of the link.

As is well known, the drive shaft for the loop taker of the machine is located beneath the machine bed and is customarily driven by means of a connecting shaft 44 carrying gear means which are designed for cooperation with gear means carried by the hook drive shaft. The interconnection between such shaft 44 and the arm shaft, being no part of the present invention and widely known to persons skilled in the art, will not be described herein. Of significance, however, is the provision by applicant of a split loop taker drive shaft comprising a first segment 45 which is operatively connected, by the aforesaid co-operating gear means, with a source of driving power such as the motor-driven arm shaft of the machine (not shown) and a second segment 46 which is operatively connected to the loop taker 18 by means of co-operable gears carried respectively by the loop taker shaft 47 which mounts the circularly movable loop taker and by second segment 46. Thus, when the first and second segments of the loop taker drive shaft are operatively connected, as will be hereinafter described, the loop taker will be rotatably driven at an angular speed which is in predetermined relationship to the cyclical reciprocation of the needle bar and needle. Depicted is a rotary hook, however, it will be readily appreciated that any of the conventional loop takers adapted to travel in circular path and cooperable with the needle in the production of stitches may be employed.

The first segment 45 of the split hook drive shaft is provided with a blind bore 48 which is dimensioned to accept the reduced diameter end 49 of the second hook drive shaft segment 46. When the shafts are so arranged the axial alignment of both segments is assured and vibrational forces generated by the rotating split shaft are minimized.

Positioned in overlying relation to the first and second segments of the hook drive shaft is sleeve 50. The purpose of the sleeve is to operatively connect the first and second segments of the hook drive shaft in a dual manner. Specifically, the sleeve is cylindrical, and at one end is provided with an elongated slot 51 which extends from the end of the sleeve inwardly. The slot is dimensioned to slidably receive a radial projection 52 carried by the first segment 45 of the hook drive shaft and locked in place by pin 66. The projection 52 is desirably formed as a unitary key member and is provided with a greater length that the external diameter of the first segment of the hook drive shaft. In this manner the said first segment may be inserted within the sleeve and transmit the rotational force received from shaft 44 via the sleeve to the second segment of the hook drive shaft. The sleeve is, thus slidable axially with respect to the first segment but rotates with such shaft segment.

The sleeve is provided at an intermediate location with a reduced diameter neck section 53 adapted to permit the seating of yoke member 41 thereon so as to permit the transmission of any longitudinal force exerted upon the yoke member by the horizontal arm thereto. The transmission of such longitudinal force results in longitudinal movement of the yoke member and sleeve 50. The sleeve is formed with its non-slotted end of reduced diameter so as to accomodate a collar 54 thereon for a purpose to be described. A radial bore 55 is formed in this end portion of the sleeve sized to receive a ball member 56 therein. The second segment of the hook drive shaft is provided with a spiral groove 57 over a portion of its external surface beginning at the interface with reduced diameter end 49. The depth and width of the groove are dimensioned to snugly seat ball member 56 therein, and the external diameter of second segment 46 is selected such that at least that portion thereof bearing the spiral groove may be positioned within sleeve 50. When so positioned, with reduced end 49 seated within blind bore 48 of the first segment, collar 54 is secured to the sleeve by means of set screw 59 such that the ball member 56 is maintained partially within bore 55 of the sleeve and partially within the spiral groove 57 of second segment 46. This construction enables the rotation of segment 46 relative to segment 45 upon longitudinal movement of yoke member 41 and sleeve 50. It also serves to operatively connect second segment 46 to first segment 45 for rotation therewith.

In order to provide for rotation of rotary hook 18, second segment 46 is provided at its end adjacent the rotary hook with a bevel gear 60. The hook shaft 47 which carries hook 18 is also provided with a bevel gear 61 adapted to mesh with the gear 60 and thereby impart rotation to the hook with its beak 62.

Shown in phantom in FIG. 2 is the bearing 58 within which the second segment 46 is journaled. The second segment is maintained in driving relationship with the hook shaft 47 by being fixed closely adjacent same with the gears of both members in meshed relation by means of collar 63 and set screw 64.

Referring to FIG. 1 there is shown a spring 65 secured at one end to the frame of the machine and at the other end to link member 33. The purpose of the spring is to bias timing shaft 31 and the cam follower into the path of rotation of skip-stitch cam 23. When so arranged control lever 22 serves to disengage the skipstitch mechanism. However, it will be understood that by suitably rearranging the spring and control lever the reverse control may be achieved.

In operation, upon actuation of the skip-stitch mechanism cam 23 rotates and engages cam follower 24 resulting in pivotal movement of lever 25 fulcrumed at 36. Timing shaft 31 is caused to rotate in a clockwise direction thereby pivoting link member 33 so as to move horizontal arm 34, link 37 and yoke 41 to the left as viewed in FIG. 1. Sleeve 50 is thereby also moved to the left, and the ball member 56 riding in spiral groove 57 effectuates a rotation of the second segment 46 of the hook drive shaft in a counterclockwise direction. Through gears 60 and 61 the hook is advanced in the counterclockwise direction such that beak 62' will be out of phase with the needle loop, thereby skipping a stitch. The surface of cam 23 is so patterned as to provide for the desired number of skipped stitches per revolution of the same. it will be understood, of course, that the hook 18 may be either advanced or retarded so as to insure the skipping of a stitch depending upon the contour provided for skip-stitch cam 23.

It will also be understood that the rotation of the second segment 46 relative to the first segment 45 through the skip-stitch mechanism does not otherwise affect the continuous rotation of hook 18 by virtue of the drive consisting of shaft 44, segment 45, sleeve 50, segment 46 and hook shaft 47.

It will be understood that various changes in the details, materials, arrangements of parts, and operating conditions which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principles and scope of the invention.

Having thus set forth the nature of the invention, what is claimed herein is:

1. in a sewing machine having a frame, a needle bar mounted for endwise reciprocation therein, stitchforming instrumentalities including a thread-carrying needle carried by said needle bar and a circularly moving loop taker cooperable with said needle in the production of stitches, and means including a rotary main shaft, for driving said needle bar and said circularly moving loop taker, the combination of skip-stitch record means movably supported on said frame and adapted to be operatively connected to said rotary main shaft, a longitudinally segmented drive shaft including a first segment operatively connectable to and drivable by said rotary main shaft and a second segment connectable between said first segment and the loop taker drive shaft, said second segment being drivable rotatably by said first segment and adapted to be rotated independently thereof by said skip-stitch record means to effectuate programmed modification of the effective circular movement of said loop taker with respect to said needle to prevent the formation of stitches.

2. A sewing machine according to claim 1, wherein a lever is pivotably mounted in said frame, said skipstitch record means is adapted to be operatively connected thereto so as to impart a predetermined pattern of pivotal movements to said lever, a timing shaft is journaled for rotation in said frame operatively engaged with said lever, said shaft also being operatively connected to a horizontal arm so as to impart longitudinal movement thereto, a slide member is carried by said horizontal arm and movable longitudinally therewith, a sleeve member is slidably mounted with respect to said first segment and rotatable therewith, said sleeve operatively connecting said slide member and first segment to said second segment for relative rotational movement thereby, whereby longitudinal movement of said slide member effectuates rotation of said second segment relative to said first segment and a corresponding change in the timing of said loop taker with respect to said needle, rotation of said second segment by said first segment being independent of the said rotation of said second segment by said slide member.

3. A sewing machine according to claim 2, wherein said intelligence record means comprises a rotatable skip-stitch cam, a first portion of said lever being formed as a cam follower adapted to be operatively engaged by said skip-stitch cam and a second portion of said lever being provided with gear teeth, the upper portion of said timing shaft being provided with gear teeth co-operable with the gear teeth of said lever whereby said timing shaft may be rotated by pivotal movement of said lever.

4. A sewing machine according to claim 3, wherein the lower portion of said timing shaft is rigidly secured to one end of a first link member, said horizontal arm being pivotably connected adjacent one end thereof to the other end of said first link member, the other end of said horizontal arm being pivotably connected to one end of a second link member mounted in the frame of the machine for pivotal movement about its other end, said slide member being carried by said second link member for pivotal movement therewith 5. A sewing machine according to claim 4, wherein said slide member is in the form of a bifurcated yoke, said sleeve member having a bore extending therethrough in axial alignment with said first and second segments of the loop taker drive shaft and dimensioned to receive said shaft segments in opposed relationship, said sleeve being generally cylindrical and provided at an intermediate section with a reduced diameter neck portion adapted to receive said yoke and to be moved longitudinally thereby with respect to said first segment, a longitudinally extending slot being formed in said sleeve adapted to slidably receive radial projections carried by said first segment.

6. A sewing machine according to claim 5, wherein said sleeve is provided, at a location adapted to overlie said second segment when same is inserted therein, with a radial bore adapted to contain a ball member partially therein, said second segment being provided over at least part of the surface thereof adapted for positioning within said sleeve with a spiral groove adapted to seat said ball member therein, a collar being provided for positioning on said sleeve over said radial bore for maintaining said ball partially within said groove whereby longitudinal movement of said yoke causes said ball to ride within said groove and effect rotation of said second segment relative to said first segment and a corresponding change in timing of said loop taker with respect to said needle.

7. A sewing machine according to claim 6, wherein said second segment of the loop taker drive shaft carries a bevel gear at the end thereof adjacent said loop taker, said loop taker being a rotary hook mounted on a hook shaft carrying a bevel gear thereon in meshed relationship with the said bevel gear on said second segment, whereby rotation of said second segment effectuates rotation of said hook shaft and hook.

8. A sewing machine according to claim 7, wherein biasing meansare provided for urging rotation of said timing shaft in a direction so as to pivot the cam fol lower of said lever into the path of rotation of said skipstitch cam for operative engagement therewith.

y 9. A sewing machine according to claim 8, wherein an operator controllable second lever is pivotably mounted in the frame thereof and is adapted to control the pivotal movement of said cam driveable lever and thereby the operative engagement of said cam follower and skip-stitch cam.

10. A sewing machine according to claim 5, wherein said radial projections of said first segment of the loop taker drive shaft comprise a unitary key member of greater length than the external diameter of said first segment, said first segment being provided with a slot extending completely therethrough and dimensioned to snugly receive said key member, apertures being formed in said key member and first segment adapted, when in alignment, to receive a pin member securing said key member to said first segment.

11. A sewing machine according to claim 3, wherein at least one portion of the surface of said skip-stitch cam is formed to effectuate pivotal movement of said lever and consequent rotation of said loop taker, so as to advance same with respect to said needle a sufficient angular distance to prevent the formation of a stitch.

12. A sewing machine according to claim 3, wherein at least one portion of the surface of said skip-stitch cam is formed to effectuate pivotal movement of said lever and consequent rotation of said loop taker so as to retard same with respect tosaid needle a sufficient angular distance to prevent the formation of a stitch. 

1. In a sewing machine having a frame, a needle bar mounted for endwise reciprocation therein, stitch-forming instrumentalities including a thread-carrying needle carried by said needle bar and a circularly moving loop taker cooperable with said needle in the production of stitches, and means including a rotary main shaft, for driving said needle bar and said circularly moving loop taker, the combination of skip-stitch record means movably supported on said frame and adapted to be operatively connected to said rotary main shaft, a longitudinally segmented drive shaft including a first segment operatively connectable to and drivable by said rotary main shaft and a second segment connectable between said first segment and the loop taker drive shaft, said second segment being drivable rotatably by said first segment and adapted to be rotated independently thereof by said skip-stitch record means to effectuate programmed modification of the effective circular movement of said loop taker with respect to said needle to prevent the formation of stitches.
 2. A sewing machine according to claim 1, wherein a lever is pivotably mounted in said frame, said skip-stitch record means is adapted to be operatively connected thereto so as to impart a predetermined pattern of pivotal movements to said lever, a timing shaft is journaled for rotation in said frame operatively engaged with said lever, said shaft also being operatively connected to a horizontal arm so as to impart longitudinal movement thereto, a slide member is carried by said horizontal arm and movable longitudinally therewith, a sleeve member is slidably mounted with respect to said first segment and rotatable therewith, said sleeve operatively connecting said slide member and first segment to said second segment for relative rotational movement thereby, whereby longitudinal movement of said slide member effectuates rotation of said second segment relative to said first segment and a corresponding change in the timing of said loop taker with respect to said needle, rotation of said second segment by said first segment being independent of the said rotation of said second segment by said slide member.
 3. A sewing machine according to claim 2, wherein said intelligence record means comprises a rotatable skip-stitch cam, a first portion of said lever being formed as a cam follower adapted to be operatively engaged by said skip-stitch cam and a second portion of said lever being provided with gear teeth, the upper portion of said timing shaft being provided with gear teeth co-operable with the gear teeth of said lever whereby said timing shaft may be rotated by pivotal movement of said lever.
 4. A sewing machine according to claim 3, wherein the lower portion of said timing shaft is rigidly secured to one end of a first link member, said horizontal arm being pivotably connected adjacent one end thereof to the other end of said first link member, the other end of said horizontal arm being pivotably connected to one end of a second link member mounted in the frame of the machine for pivotal movement about its other end, said slide member being carried by said second link member for pivotal movement therewith
 5. A sewing machine according to claim 4, wherein said slide member is in the form of a bifurcated yoke, said sleeve member having a bore extending therethrough in axial alignment with said first and second segments of the loop taker drive shaft and dimensioned to receive said shaft segments in opposed relationship, said sleeve being generally cylindrical and provided at an intermediate section with a reduced diameter neck portion adapted to receive said yoke and to be moved longitudinally thereby with respect to said first segment, a longitudinally extending slot being formed in said sleeve adapted to slidably receive radial projections carried by said first segment.
 6. A sewing machine according to claim 5, wherein said sleeve is provided, at a location adapted to overlie said second segment when same is inserted therein, with a radial bore adapted to contain a ball member partially therein, said second segment being provided over at least part of the surface thereof adapted for positioning within said sleeve with a spiral groove adapted to seat said ball member therein, a collar being provided for positioning on said sleeve over said radial bore for maintaining said ball partially within said groove whereby longitudinal movement of said yoke causes said ball to ride within said groove and effect rotation of said second segment relative to said first segment and a corresponding change in timing of said loop taker with respect to said needle.
 7. A sewing machine according to claim 6, wherein said second segment of the loop taker drive shaft carries a bevel gear at the end thereof adjacent said loop taker, said loop taker being a rotary hook mounted on a hook shaft carrying a bevel gear thereon in meshed relationship with the said bevel gear on said second segment, whereby rotation of said second segment effectuates rotation of said hook shaft and hook.
 8. A sewing machine according to claim 7, wherein biasing means are provided for urging rotation of said timing shaft in a direction so as to pivot the cam follower of said lever into the path of rotation of said skip-stitch cam for operative engagement therewith.
 9. A sewing machine according to claim 8, wherein an operator controllable second lever is pivotably mounted in the frame thereof and is adapted to control the pivotal movement of said cam driveable lever and thereby the operative engagement of said cam follower and skip-stitch cam.
 10. A sewing machine according to claim 5, wherein said radial projections of said first segment of the loop taker drive shaft comprise a unitary key member of greater length than the external diameter of said first segment, said first segment being provided with a slot extending completely therethrough and dimensioned to snugly receive said key member, apertures being formed in said key member and first segment adapted, when in alignment, to receive a pin member securing said key member to said first segment.
 11. A sewing machine according to claim 3, wherein at least one portion of the surface of said skip-stitch cam is formed to effectuate pivotal movement of said lever and consequent rotation of said loop taker so as to advance same with respect to said needle a sufficient angular distance to prevent the formation of a stitch.
 12. A sewing machine according to claim 3, wherein at least one portion of the surface of said skip-stitch cam is formed to effectuate pivotal movement of said lever and consequent rotation of said loop taker so as to retard same with respect to said needle a sufficient angular distance to prevent the formation of a stitch. 